Non-linearity determination of positioning scanner of measurement tool

Abstract

Determination of non-linearity of a positioning scanner of a measurement tool is disclosed. In one embodiment, a method may include providing a probe of a measurement tool coupled to a positioning scanner; scanning a surface of a first sample with the surface at a first angle relative to the probe to attain a first profile; scanning the surface of the first sample with the surface at a second angle relative to the probe that is different than the first angle to attain a second profile; repeating the scannings to attain a plurality of first profiles and a plurality of second profiles; and determining a non-linearity of the positioning scanner using the different scanning angles to cancel out measurements corresponding to imperfections due to the surface of the sample. The non-linearity may be used to calibrate the positioning scanner.

1. A method comprising:
 providing a probe of a measurement tool coupled to a positioning scanner; 
 scanning a surface of a sample with the surface at a first angle relative to the probe to attain a first profile, wherein the first angle is substantially 90° relative to the probe; 
 scanning the surface of the first sample with the surface at a second angle relative to the probe that is different than the first angle to attain a second profile, the second angle being able to be any angle that results in a predetermined amount of lateral travel of the probe; 
 repeating the scannings to attain a plurality of first profiles and a plurality of second profiles; and 
 determining a non-linearity of the positioning scanner using the different scanning angles to cancel out measurements corresponding to imperfections due to the surface of the sample. 
 
     
     
       2. The method of  claim 1 , wherein the probe is a non-contacting probe. 
     
     
       3. The method of  claim 1 , wherein the sample includes a patterned integrated circuit (IC) chip. 
     
     
       4. The method of  claim 1 , wherein the second angle is approximately 81° relative to the probe. 
     
     
       5. The method of  claim 1 , further comprising:
 measuring a calibrated Z height measurement sample; and 
 calibrating the entire Z range of the measurement tool based on the Z height measurement sample. 
 
     
     
       6. The method of  claim 1 , wherein the measurement tool includes a scanning probe microscope (SPM). 
     
     
       7. The method of  claim 1 , wherein the determining includes:
 averaging the plurality of first profiles and averaging the plurality of second profiles; 
 fitting the averaged first profiles and the averaged second profiles to a first order best-fit line and calculating residuals from the first order best-fit lines; 
 aligning the residuals of the averaged first profiles and the residuals of the averaged second profiles; 
 subtracting the residuals of averaged first profiles from the residuals of the averaged second profiles; and 
 evaluating a result of the subtracting to identify the non-linearity of the positioning scanner.